Railway and Commercial Vehicle

LS-DYNA Simulations of the Impacts of a 38-Ton Heavy Goods Vehicle into a Road Cable Barrier

Nowadays, more and more attention is being paid to safety on roads and motorways. It is due to the continuous development of road and motorway network and a significant increase of the number of vehicles on roads. To meet the expectations of improving road safety in Poland, the Road Innovations Development (RID) research programme was implemented in 2016. The aim of the RID 3A - Road Safety Equipment (RoSE) project is a comprehensive analysis of various road restraint systems and various types of road safety equipment installed on roads and bridges. The RID 3B - Effect of time and operating conditions of the durability and functionality of the elements of road safety (LifeRoSE) complementary project is aimed at developing innovative and comprehensive road management methodology for road safety equipment and traffic management measures. Part of the aforementioned projects is a thorough study of safety barriers based, among others, on full-scale crash tests and a number of numerical simulations using LS-DYNA. The aim of the paper is to assess the crashworthiness of a road cable barrier during an impact of a Heavy Goods Vehicle (HGV) weighing 38 tons. A numerical model of the safety device was developed and validated with a full-scale crash test. Based on this computational model, a series of virtual crash tests were carried out in which the HGV collides with the barrier under various impact conditions. Some of the cases will be compared with real accident outcome that took place on highway in Poland.

Transient Dynamic Implicit Analysis for Durability Testing of Bus Seats

A core challenge to any finite element analysis (FEA) is figuring out loads and how to apply them. For static events, it is usually straightforward. In the case of durability testing, loads are obtained from accelerometers mounted on vehicles that are driven for hours, if not days on test tracks or routes that hopefully replicate the most severe road conditions possible. These accelerations can then be numerically processed and used for various frequency domain analyses such as a random vibration analysis (i.e., PSD), a frequency response analysis, or steady state dynamics. Although powerful and useful, these solution sequences are all based on the linear normal modes response and do not account for the nonlinear evolution of the structure as it shakes, rattles and rolls. As for a nonlinear material response, forget about it. Our approach is to describe how one can take the full acceleration time history and with little sacrifice in accuracy, perform a nonlinear, transient dynamic implicit analysis over a time span of 5 to 10 seconds. The reason for choosing implicit analysis is based on two factors: (i) the necessity for finely detailed meshes in regions of high-stress, and (ii) quick solution times. A series of bus seats was analyzed using this technique and showed good validation against test track data. From a simulation viewpoint, this work could not have been accomplished without the use of the implicit solver since run times were in hours whereas trial explicit runs indicated run times in days on equivalent hardware running with 32 CPU-cores.